Percutaneous absorption has recently been adopted as a means for administering a drug into a living body, which comprises adhering a drug-containing pressure-sensitive adhesive sheet to a skin of a living body. The drug-containing pressure-sensitive adhesive sheet generally comprises a support made of a synthetic resin, such as polyester or polyethylene, having formed on one side thereof a pressure-sensitive adhesive layer containing a drug for percutaneous absorption, with the surface of the adhesive layer being covered with a separator. Such a drug-containing pressure-sensitive adhesive sheet is usually packaged with an individual packaging material impermeable to moisture so as to prevent volatilization of the drug contained therein and to prevent the influences of moisture on the drug.
In the case of individually packaging the drug-containing pressure-sensitive adhesive sheet as above, if the adhesive is squeezed out from the extremities of the sheet, the adhesive squeezed out adheres to the inside of the packaging material, making it difficult to take out the drug-containing pressure adhesive sheet from the packaged body.
Where the pressure-sensitive adhesive layer contains a plasticizer, a tackifier or a liquid component, there is a tendency that these substances ooze out from the extremities of the sheet, go around to the back of the support or separator, and adhere to the inside of the packaging material, and as a result, the drug-containing pressure-sensitive adhesive sheet is adhered to the inside of the packaging material, making it difficult to take out the sheet from the packaged body at the use thereof.
Further, in packaging the drug-containing pressure-sensitive adhesive sheet cut into a predetermined size, if the sheet cut are temporarily piled, a problem occurs that the slippability between the sheets deteriorates due to the squeeze-out of the pressure-sensitive adhesive or the go-around of the plasticizer as same as above, and the workablility of the packaging is greatly reduced.
In order to overcome these problems, it has been proposed to (1) use an oversized separator or (2) to provide projections serving as a spacer on the periphery of an oversized separator as disclosed in JP-B-U-4-51782 (the term "JP-B-U" as used herein means an "examined published Japanese utility model application").
According to method (1), the adhesive can be prevented from adhering to the inside of the packaging material and a plasticizer can be prevented from going around to the back of the separator. However, a problem still exists that the plasticizer, etc. tend to go around to the back of the support.
According to method (2), the projections serving as a spacer are effective to eliminate the problem of method (1). However, to use an oversized separator leads to an increased cost and a decreased yield, and special equipment is needed to provide projections on the periphery of the separator. Therefore, this method is not economical.